This invention relates to valuable cards, instruments and documents and, in particular to methods and apparatus for patterning or encoding these cards, instruments and documents.
For ease of discussion, the invention will be illustrated using cards such as commonly used plastic cards. However, it should be understood that in the specification to follow and in the appended claims, when reference is made to "cards", instruments and documents are also included, although not specifically identified as such.
Cards of interest may be used, for example, to identify a person or object and/or they may be used as a value card (i.e. a debit card or credit card) to withdraw money from a machine. Because of the value of these cards there are counterfeiters who make "false" cards which attempt to imitate "true" or "valid" cards. To enhance the security of the cards it is known to add additional security "features" to the surface of the cards. These added security features can take the form of a hologram or a spatial dependent optical image or ghost images strategically placed on the surface of the card.
In a certain group of applications the security features are dependent on a person actually checking that the cards' security features are present and/or intact. A problem exists with these applications in that there are many instances where the person responsible for checking the validity of the card, such as a cashier, does not actually look at the credit card and simply mechanically "swipes" the card through a card reader, such as a slot reader. When this occurs, the security features present on the card such as the hologram on the surface of the card and the signature on the back of the card are rendered useless.
It is therefore desirable and/or necessary to develop a more reliable and automatic means for impeding the falsification of a card and to check whether these means are present. To this end, card readers may be used to automatically read or sense the security related information contained on a card to identify whether a card is valid. Also, to increase the security of the cards more features may be added to make it much more difficult to counterfeit these cards. Examples of means for enhancing the security of cards and for sensing (reading) the presence of the enhanced security means are described, for example, in our presently pending patent applications, identified below, the teachings of which are incorporated herein by reference: (a) Multi Sensor Information Reader filed Apr. 7, 1998 and bearing serial number 09/056134, and (b) Method And Apparatus For Impeding The Counterfeiting Of Cards, Instruments And Documents filed May 26, 1996 and bearing serial number 09/084,844.
A disadvantage of increasing the number of security features placed on the top and bottom surfaces of a card is that it uses up valuable space, which many card manufacturers would prefer to use for advertising. This disadvantage is overcome in cards made in accordance with the invention.